Mario Belamaric wrote:Looking at the cows I wouldn't say they are underexposed. They are black! It looks to me that blacks are lifted in those cows. Look at the grass around. It's almost overexposed. In any case I see the point that he's trying to clear.

Dara O'Neill wrote:...or else I am using the term FPN incorrectly. My issue is that I see what appear to be hundreds of thin vertical lines...

You're using the term correctly for that. The columns on the sensor will have a different fixed bias from one another, which will be apparent in the really dark areas like the ones you show. All CMOS cameras will have this.

The trick is remembering that the BMD cameras do very little to assist dealing with this automatically. They leave most (if not all) of the image processing to you. A common practice is to ETTR as much as possible without clipping anything vital, then either leave the black level where it is, or dropping it to hide the FPN (which is what many other cameras do). You never want to lift the black level with BMD cameras.

I suppose what I am getting at is that I feel like my camera might be affected worse than the regular models. In my test above I was trying to replicate the conditions under which this user got a "super clean" image at ISO 800 from his Ursa 4.6k:

As you can see my image is nowhere near super clean, it's very dirty. Almost every shot I've taken with my UMB has those FPN lines faintly in a part of the image.

I'm uploading a video file of the FPN which I'll link to here in the morning.

Dara O'Neill wrote:I completed the candle light test... lots of FPN! Maybe you guys could take a look at these vertical lines in the mid tones and tell me is this is considered normal for the sensor.

A grade will do no good here because it is a light and dark pattern on mid tones.

I don't see any midtones in your image.

The test for me is to look at where the blacks are sitting.

When I open your image in a new tab I can see that the blackest darkest part of your image is STILL brighter than the black of the surround of the image.

Let's call the back of the image surround a reference black.

If your exposed image is dark, then something dark should actually be black. Not light milky black but still with no meaningful picture information. The blacks in your exposed image are elevated across the board.

Your blacks aren't black. They're light black.

If you were to apply a tone curve (grade) that made something in your exposed image that has no picture detail anyway, the same brightness black as the surround, then you might find the FPN print's differently.

I shoot in very dark situations all the time.

Here's a post with some frames in another thread. Notice when you open the images, the blacks are...you know...black ! They sit closer to the image surround reference black.

You shouldnt see FPN in daylight footage. You shouldn't see it in any but the most stressed exposure images. If you are then you may have an issue with your camera and it would be for BMD to decide that. I'd take it up with them, but from your candlelight images, I'd want to see a more normal curve applied first....

@Earl R. Thurston @Robert Niessner - I know he down scaled and compressed but if we believe he was telling the truth when he said his image was "super clean" at ISO 800 in candle light, you can also now download my footage here to compare (9seconds, 1gb), interested to hear your thoughts:

@CaptainHook - Yes, I worked this out before the test, definitely helps the blue shadows, however you can see in the video above that it doesn't help the FPN in the light.

@John Brawley - First can I say I love your images. I really appreciate your detailed response so I hope you can continue this conversation, a few issues re: my milky blacks...

- My stills and footage were shot RAW and are ungraded.

- Applying a grade like you suggested does darken the areas, making the FPN harder to see, unless you have a monitor / screen at a higher brightness setting which then makes the FPN even worse and more prominent because the FPN itself is a pattern of dark on light:

Raise brightness level of monitor to inspect FPN

Blacks black but FPN worse_1.5.1.png (824.39 KiB) Viewed 6641 times

- Original test that I was replicating was also shot at native ISO 800, with milky blacks, but has no FPN:

- I would be more than happy with the level of noise you get in your images, noise is not my issue, it's the vertical pattern of thin lines that's overlayed on top of the image, it distracts from the image itself, it's like an extra layer of film over what's being viewed, please check out my candle light footage to view (9secs, 1gb):

- Thanks again for your detailed input, re: taking it up with BMD, should I first go to my reseller or to BMD directly or both? Should I get it refunded while I still can and let them send me a new one?

Dara O'Neill wrote:- My stills and footage were shot RAW and are ungraded.

Where I would always expect to be able to see some FPN in difficult conditions on any Ursa Mini 4.6K.

Dara O'Neill wrote:- Applying a grade like you suggested does darken the areas, making the FPN harder to see, unless you have a monitor / screen at a higher brightness setting which then makes the FPN even worse and more prominent because the FPN itself is a pattern of dark on light:

I don't see it under those conditions, but if you are / do, then we have a different threshold for it.

The grade you apply was also heavy handed. With a skilled colourist, I think you'd be able to find something less crushed in the blacks, yet that has the blacks being black.

Dara O'Neill wrote:- Original test that I was replicating was also shot at native ISO 800, with milky blacks, but has no FPN:

I suspect that you have a different lens and a different exposure. What lens did you use and at what exposure ?

What's in the image seems different to me. What amount of light is reflected will be different. It's hard to "replicate" this without everything being the same.

The linked image also appears to be "somewhat" graded to me, the blacks are sitting lower than straight ungraded BMD LOG.

Dara O'Neill wrote:- Thanks again for your detailed input, re: taking it up with BMD, should I first go to my reseller or to BMD directly or both? Should I get it refunded while I still can and let them send me a new one?

BMD would be the ones I imagine, but if you're inside your re-seller's return period perhaps take it up with them first and see how they feel.

To be honest, I'm not sure you've made a very compelling case YET for there being an issue, I think so far in the circumstances that you're testing for, almost all BMD cameras would behave in a similar way. But I can't really tell over the internet

Thanks for your reply. It is certainly frustrating that I can't have you here to see this but please just believe me that there noise in my image has strong vertical lines. In your dark images you have regular acceptable noise without the lines.

Please look at the footage I uploaded below, you didn't seem to address it in your answer. It's the closest thing to looking through my camera that I can offer.

Dara O'Neill wrote:- I would be more than happy with the level of noise you get in your images, noise is not my issue, it's the vertical pattern of thin lines that's overlayed on top of the image, it distracts from the image itself, it's like an extra layer of film over what's being viewed, please check out my candle light footage to view (9secs, 1gb):

Dara O'Neill wrote:Thanks for your reply. It is certainly frustrating that I can't have you here to see this but please just believe me that there noise in my image has strong vertical lines. In your dark images you have regular acceptable noise without the lines.

Please look at the footage I uploaded below, you didn't seem to address it in your answer. It's the closest thing to looking through my camera that I can offer.

Dara O'Neill wrote:- I would be more than happy with the level of noise you get in your images, noise is not my issue, it's the vertical pattern of thin lines that's overlayed on top of the image, it distracts from the image itself, it's like an extra layer of film over what's being viewed, please check out my candle light footage to view (9secs, 1gb):

I downloaded your file. Based on this ProRes file alone, I'd say it's simply far too underexposed and has the wrong white balance on top of that. An incorrect white balance is a problem on any camera when you get to the edges of over or underexposure. When I view the shot in ACES in Resolve, I don't see FPN. All I can say for sure is that it's a lot darker than Daniel Peter's shots that you posted the link to. It would be much better if you posted a raw file as that would eliminate ISO and white balance discrepancies. Retest and record a raw file and post it with the f-stop and lens you captured it at. That would allow people here more information with which to provide feedback on the image.

Thanks for taking a look but as you can see above it was shot RAW, changing ISO and WB doesn't remove the FPN lines. ACES helps to hide them in the dark but I can still see the linear FPN clearly when using ACES with the original RAW files. If needed I'll shoot another test at dusk this evening to mimic John's dark shot and upload the small RAW file for you so you can give these FPN lines some further inspection. Thanks

Assuming you check the camera histogram when setting exposure, is your data bumping up against the dark end? If I'm even close to 0 values I try to fix that before shooting. Even with that, I've been shooting some Pro Res HD with my UMP that is getting pretty close and I haven't seen any noise.

With my Production 4K, it was/is a constant threat if I'm on the wrong end of the histogram. Even had some show up on a white car but not in the dark parts of the scene.

And the first thing I'd try is Rick Lang's suggestion to slow down the shutter and use 360 degrees. Essentially double the light if the blur is OK (might want that on the candles anyway). Wish I'd thought of this obvious solution before.

I am actually now really excited and happy by what it could do in low light. I was pretty worried when I first saw the FPN but over the last week I've learned so much about the UMP and Resolve from going on this journey so I thank you all sincerely for your input. Very excited now to get out and start shooting properly.

The colour temperature and tint of the post of the cows are way off. Play with that in Resolve to raise the temperature. I don't know what it was recorded in, but it may look better as you increase the temperature perhaps up to 6500K.

As for the dynamic range illustrated by the red (blown) window. Make sure you don't have recording in Video turned On in the camera. Always record in Film whether raw or ProRes. Don't use a Video LUT in camera as discussed previously. If this scene was recorded in raw (Film) or ProRes Film, sometimes you can blow a highlight on the camera, but for the most part still save it in Resolve. Always set video levels in Resolve to Full and turn on Soft Clipping and Highlight Recovery when those options are available. You may need to use secondary colour correction with a power window to bring that window down to where you feel it should be.

And don't be afraid to let an exterior look like an exterior when you're shooting interior. You don't want the levels to match, just come down as long as you aren't really clipping which the Resolve scopes will illustrate as you pull down the Gain or highlights (or even bring down everything evenly via the Offset adjustment). I prefer grading in Log mode now. Very interesting way to grade.

My month of shooting and editing two client videos a week is over. This last week had both two shoots and several school related activities for the girls (and sometimes the wife and me) that last of which just ended a few minutes ago. The all-night grad was so much fun though. And I get to do it again next June when my girls graduate!

Looking forward to some relaxed vacation time so I can start learning Resolve 14... and start using my new Misfit Atom Top Flag that came in a box so light, I joked with the delivery man that it must be empty.

My computer is down at the moment so I can't do any downloads, BUT, I would say at these light levels, even a difference of 1/2 a stop in exposure on the lens can make a HUGE difference to how salvageable a shot can be.

Dara O'Neill wrote: If needed I'll shoot another test at dusk this evening to mimic John's dark shot and upload the small RAW file for you so you can give these FPN lines some further inspection. Thanks

Yes John, I had no idea just how much of an effect half a stop could make to the image quality. I now know how thin the line is. I'm actually very happy with it's low light performance after the dusk tests. Thank you very much for all your input.

And thanks for getting back to me Rick, I know you were busy, I got it sorted now. False colour is the way!

Very good, Dara. Up at 4:15 am today to tackle this issue... okay, just kidding, off to the ferry to Vancouver with the girls in a few minutes.

I've been shooting almost directly into the sun low in the sky and that's a difficult exposure too, but I shoot now with false colour on most of the time (since exterior lighting can change in small ways every few minutes) to nail my exposure shot to shot on skin tones.

Does that work? Yes, I actually coloured Wednesday's video with nearly 80 shots in about ten minutes without a single troublesome clip. Never done anywhere near that well before as it used to take hours. I do the first clip carefully and then after that it's a simple copy to the other clips with minor tweaks of the colour temperature and one or more of the lift, gamma, gain (using Log mode) and never had to do a secondary or curve this time. Very pleased with that. Now this isn't fine art we're talking about but illustrates how fast everything can go when each exposure is near perfect.

Shoot a short raw clip and then in Resolve, render the output in the Deliver page using your source media with the best quality debayer and a best quality codec. Check and see if that's improved everything.

just purchased UMP4.6k. getting a ton of fixed pattern noise in ungraded images. i have two bmpccs and the bmcc 2.5k and i don't get this under the same conditions at all. yes i will get noise, but not this fixed noise that looks like its baked on the sensor itself. I've tried the calibration which has done nothing. really not understanding this.

dephipps wrote:just purchased UMP4.6k. getting a ton of fixed pattern noise in ungraded images. i have two bmpccs and the bmcc 2.5k and i don't get this under the same conditions at all. yes i will get noise, but not this fixed noise that looks like its baked on the sensor itself. I've tried the calibration which has done nothing. really not understanding this.

What software are you running in your camera? Mine was doing this on 'normal' interior shots that were sometimes even evenly exposed (I would notice it on black shirts), but now that I have installed 4.4 on my camera and completed a calibration the noise is gone, even on shots I thought would have it.

dephipps wrote:just purchased UMP4.6k. getting a ton of fixed pattern noise in ungraded images. i have two bmpccs and the bmcc 2.5k and i don't get this under the same conditions at all. yes i will get noise, but not this fixed noise that looks like its baked on the sensor itself. I've tried the calibration which has done nothing. really not understanding this.

Do you maybe have the in-camera sharpening set to on? Because this is not thought for recording, only for live video.

Dara O'Neill wrote:Yes John, I had no idea just how much of an effect half a stop could make to the image quality. I now know how thin the line is. I'm actually very happy with it's low light performance after the dusk tests. Thank you very much for all your input.

And thanks for getting back to me Rick, I know you were busy, I got it sorted now. False colour is the way!

Dear Dara, I'm a bit late to the conversation, but I would really appreciate it if you could clarify this for me. I have the same problem with FPN lines as you did. Although it seemed to be all good on location and the lighting was okay and seemed exposed well.

I just want to ask what was the exact solution for you - to shoot in better light, use false color, and half a stop difference (as in, lets say go from 1.4 to 1.2)? I would really appreciate it if you could explain this!Thank you!